In an ultrasonic diagnostic device, ultrasonic transducers convert electrical signals into ultrasonic waves that propagate in human tissue and convert the ultrasonic waves reflected back by the human tissue into electrical signals. The electrical signals can be processed and displayed on a display device as images for analysis and disease diagnosis by s doctor.
Bandwidth is an important characteristic for measuring the quality of an ultrasonic transducer. Wideband ultrasonic transducers can transmit and receive ultrasonic waves with different frequencies so as to satisfy different requirements, such as when the diagnostic device uses different operating frequencies in near field and far field. Furthermore, a wideband ultrasonic transducer can be used in harmonic imaging. With a wide frequency band, the multiple harmonics of sound waves generated in human tissues can be received, and thereby the axial resolution and sensitivity of the images can be increased.